Genetic and Biochemical Analysis of Magnetosome Formation in Magnetospirillum gryphiswaldense

Jogler, Christian; Schüler, Dirk

doi:10.1002/9783527619443.ch9

Cited by 8 publications

(7 citation statements)

References 40 publications

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“…As protons are released in stoichiometric amounts during magnetite synthesis, the solution within the MM compartment has to be sufficiently buffered to ensure that the solubility product of magnetite is always exceeded (Cornell & Schwertmann, 2003; Faivre et al , 2004). It has been speculated that specific magnetosome proteins such as MamN, which exhibits some similarity to H + ‐translocating proteins, might mediate active H + efflux from the magnetosome compartment (Jogler & Schüler, 2007). Another magnetosome protein, MamT, contains two conserved putative cytochrome c heme‐binding sites and thus might represent a redox‐active protein, which could be responsible for redox mediation of iron within the MM compartment (Jogler & Schüler, 2007).…”

Section: Biomineralization Of Magnetite Crystalsmentioning

confidence: 99%

“…The existence of a mobile magnetosome island might also explain the widespread occurrence of magnetic phenotypes among various unrelated Proteobacteria and the phylum Nitrospira (Amann et al , 2006). It can be speculated that magnetosome genes have evolved only once, and different bacteria may have acquired magnetosome genes via horizontal gene transfer, which would have been facilitated by clustering all required genes within a compact MAI (Jogler & Schüler, 2006, 2007).…”

Section: Genomics and Genetics Of Magnetosome Formationmentioning

confidence: 99%

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Genetics and cell biology of magnetosome formation in magnetotactic bacteria

2008

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The ability of magnetotactic bacteria (MTB) to orient in magnetic fields is based on the synthesis of magnetosomes, which are unique prokaryotic organelles comprising membrane-enveloped, nano-sized crystals of a magnetic iron mineral that are aligned in well-ordered intracellular chains. Magnetosome crystals have species-specific morphologies, sizes, and arrangements. The magnetosome membrane, which originates from the cytoplasmic membrane by invagination, represents a distinct subcellular compartment and has a unique biochemical composition. The roughly 20 magnetosome-specific proteins have functions in vesicle formation, magnetosomal iron transport, and the control of crystallization and intracellular arrangement of magnetite particles. The assembly of magnetosome chains is under genetic control and involves the action of an acidic protein that links magnetosomes to a novel cytoskeletal structure, presumably formed by a specific actin-like protein. A total of 28 conserved genes present in various magnetic bacteria were identified to be specifically associated with the magnetotactic phenotype, most of which are located in the genomic magnetosome island. The unique properties of magnetosomes attracted broad interdisciplinary interest, and MTB have recently emerged as a model to study prokaryotic organelle formation and evolution.

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Section: Biomineralization Of Magnetite Crystalsmentioning

confidence: 99%

Section: Genomics and Genetics Of Magnetosome Formationmentioning

confidence: 99%

Genetics and cell biology of magnetosome formation in magnetotactic bacteria

2008

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“…In Magnetospirillum gryphiswaldense a large set of genes implicated in magnetotaxis is clustered within a genomic magnetosome island (MAI) (Schübbe et al ., 2003; Ullrich et al ., 2005; Jogler and Schüler, 2007), harbouring most magnetosome genes (Richter et al ., 2007). The closely related strains Magnetospirillum magneticum and M. magnetotacticum show a similar magnetosome gene organization (Grünberg et al ., 2001; Fukuda et al ., 2006; Jogler and Schüler, 2007). As has been found in so‐called pathogenicity islands (PAI) (Dobrindt et al ., 2004), the MAI was reported to exhibit several characteristic features of a typical genomic island, such as the presence of direct repeats (DRs), an abundance of transposases, tRNAs, and many hypothetical genes.…”

Section: Introductionmentioning

confidence: 99%

“…In Magnetospirillum gryphiswaldense a large set of genes implicated in magnetotaxis is clustered within a genomic magnetosome island (MAI) (Schübbe et al, 2003;Ullrich et al, 2005;Jogler and Schüler, 2007), harbouring most magnetosome genes (Richter et al, 2007).…”

Section: Introductionmentioning

confidence: 99%

Comparative analysis of magnetosome gene clusters in magnetotactic bacteria provides further evidence for horizontal gene transfer

Jogler

Kube

Schübbe

et al. 2009

Environmental Microbiology

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137

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The organization of magnetosome genes was analysed in all available complete or partial genomic sequences of magnetotactic bacteria (MTB), including the magnetosome island (MAI) of the magnetotactic marine vibrio strain MV-1 determined in this study. The MAI was found to differ in gene content and organization between Magnetospirillum species and strains MV-1 or MC-1. Although a similar organization of magnetosome genes was found in all MTB, distinct variations in gene order and sequence similarity were uncovered that may account for the observed diversity of biomineralization, cell biology and magnetotaxis found in various MTB. While several magnetosome genes were present in all MTB, others were confined to Magnetospirillum species, indicating that the minimal set of genes required for magnetosome biomineralization might be smaller than previously suggested. A number of novel candidate genes were implicated in magnetosome formation by gene cluster comparison. Based on phylogenetic and compositional evidence we present a model for the evolution of magnetotaxis within the Alphaproteobacteria, which suggests the independent horizontal transfer of magnetosome genes from an unknown ancestor of magnetospirilla into strains MC-1 and MV-1.

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“…In strains of Magnetospirillum, it was shown that magnetosomes consist of magnetite (Fe 3 O 4 ) crystals enclosed by a dedicated phospholipid membrane. The magnetosome membrane (MM) contains a specific set of proteins (1)(2)(3), which direct the biomineralization of highly ordered crystals along actin-like cytoskeletal filaments that control the assembly and intracellular positioning of a linear magnetosome chain (4)(5)(6)(7). Synthesis of magnetosomes has recently emerged as a model for prokaryotic organelle formation and biomineralization (8)(9)(10)(11).…”

mentioning

confidence: 99%

Conservation of proteobacterial magnetosome genes and structures in an uncultivated member of the deep-branchingNitrospiraphylum

Jogler

Wanner

Kolinko

et al. 2010

Proc. Natl. Acad. Sci. U.S.A.

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107

172

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Magnetotactic bacteria (MTB) are a phylogenetically diverse group which uses intracellular membrane-enclosed magnetite crystals called magnetosomes for navigation in their aquatic habitats. Although synthesis of these prokaryotic organelles is of broad interdisciplinary interest, its genetic analysis has been restricted to a few closely related members of the Proteobacteria, in which essential functions required for magnetosome formation are encoded within a large genomic magnetosome island. However, because of the lack of cultivated representatives from other phyla, it is unknown whether the evolutionary origin of magnetotaxis is monophyletic, and it has been questioned whether homologous mechanisms and structures are present in unrelated MTB. Here, we present the analysis of the uncultivated "Candidatus Magnetobacterium bavaricum" from the deep branching Nitrospira phylum by combining micromanipulation and whole genome amplification (WGA) with metagenomics. Target-specific sequences obtained by WGA of cells, which were magnetically collected and individually sorted from sediment samples, were used for PCR screening of metagenomic libraries. This led to the identification of a genomic cluster containing several putative magnetosome genes with homology to those in Proteobacteria. A variety of advanced electron microscopic imaging tools revealed a complex cell envelope and an intricate magnetosome architecture. The presence of magnetosome membranes as well as cytoskeletal magnetosome filaments suggests a similar mechanism of magnetosome formation in "Cand. M. bavaricum" as in Proteobacteria. Altogether, our findings suggest a monophyletic origin of magnetotaxis, and relevant genes were likely transferred horizontally between Proteobacteria and representatives of the Nitrospira phylum.M agnetotactic bacteria (MTB) are widespread aquatic microorganisms that use unique intracellular organelles called magnetosomes to navigate along the earth's magnetic field while searching for growth-favoring microoxic zones within stratified sediments. In strains of Magnetospirillum, it was shown that magnetosomes consist of magnetite (Fe 3 O 4 ) crystals enclosed by a dedicated phospholipid membrane. The magnetosome membrane (MM) contains a specific set of proteins (1-3), which direct the biomineralization of highly ordered crystals along actin-like cytoskeletal filaments that control the assembly and intracellular positioning of a linear magnetosome chain (4-7). Synthesis of magnetosomes has recently emerged as a model for prokaryotic organelle formation and biomineralization (8-11). The trait of magnetotaxis is widely spread among Proteobacteria including members from the α-, δ-and γ-subdivisions, as well as uncultivated species from the deep branching Nitrospira phylum (8). The presence of MTB within unrelated lines of various phylogenetic groups, as well as their stunning diversity with respect to magnetosome shape, composition, and intracellular organization lead to speculations of whether the evolutionary origin of magnetota...

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Genetic and Biochemical Analysis of Magnetosome Formation in Magnetospirillum gryphiswaldense

Cited by 8 publications

References 40 publications

Genetics and cell biology of magnetosome formation in magnetotactic bacteria

Genetics and cell biology of magnetosome formation in magnetotactic bacteria

Comparative analysis of magnetosome gene clusters in magnetotactic bacteria provides further evidence for horizontal gene transfer

Conservation of proteobacterial magnetosome genes and structures in an uncultivated member of the deep-branchingNitrospiraphylum

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